On the interaction of NLS-described modulating pulses with different carrier waves

We give a detailed analysis of the interaction of two modulating pulse solutions of a nonlinear wave equation. These solutions consist of pulse-like envelopes satisfying approximately a nonlinear Schrodinger equation, advancing in the laboratory frame, and modulating underlying wave trains. We improve the bound for the possible shift of the envelopes caused by the interaction of two well-prepared pulses from order (oscr)(1) to order (oscr)(epsilon). Thus, we manifest the statement that there is almost no interaction of pulses with different carrier waves.